1. Field of the Invention
The field of the invention relates generally to magnet assemblies and methods for temperature control of the magnet assemblies. More particularly, this disclosure relates to magnet assemblies equipped with temperature control elements on iron shields thereof and methods for temperature control of the magnet assemblies.
2. Background of the Invention
Magnets, such as superconducting magnets, permanent magnets, and/or resistive magnets, have been used in various applications, for example, in magnetic resonance imaging (MRI) applications. Generally, magnets are magnetically shielded to prevent the magnetic field created by such magnets from adversely interacting with electronic equipment located near the magnets. Some techniques for magnetically shielding such magnets include active and/or passive shielding.
Typically, passively shielded magnets, such as passively shielded superconducting magnets, are employed in some applications since passive shielding is more cost-effective than active shielding. Passive shielding generally employs iron shields (iron yokes) for shielding of magnets. However, magnetic properties of iron shields vary with variation of temperatures. As a result, magnetic fields generated by such magnets are unstable and fluctuate due to the variation of the temperatures of the iron shields, which is disadvantageous to the magnetic fields.
There have been attempts to provide temperature control for passively shielded magnets, such as active temperature control configurations. Such active configurations typically employ multiple temperature sensors that monitor the temperature of the iron shields and a controller that uses the data from the temperature sensors to control heaters to keep the system within a temperature range according to some control algorithm such as a Proportional-Integral-Derivative (PID) control algorithm. Such active control adds complexity and cost to the temperature system.
There is a continued need for new and improved magnet assemblies and methods for temperature control of the magnet assemblies.